Gas-Phase Acetone Condensation over Hydrotalcite-like Catalysts

摘要

Self-condensation of acetone is considered a reaction catalyzed typically by bases. In this study a flow microreactor has been used to evaluate the performance of several calcined MgZnAl hydrotalcite-like materials (HTs). The main products were mesityl oxide and aldol compounds. The nature of the catalyst's composition, i.e., the effect of Zn loading on the reaction intermediates and by-products was reported. In order to give an overall description of the base catalyzed oligomerization of acetone in gas phase, a suitable mechanism was proposed. When increasing the Zn content in the hydrotalcite structure, the activity for the acetone's oligomerization increased and the selectivity to mesityl oxide reached values about 88% mol. The most active catalyst was the one with the higher Zn content. An interpretation in function of the adsorption-desorption equilibrium of products was proposed, which discloses that the product's desorption is slow in strong basic sites. Therefore, the activity and selectivity on calcined HTs could be easily regulated by controlling the nature and amount of cations.